OK, this one's for you Frank:
Webguide was bought by Microsoft and made a free upgrade to all Media Center users. It basically streams all video, music, photos and TV across the net. It even re-encodes HD streams to lesser pixel counts.
There's compatibility with WM6 and Windows, but it seems like many browsers should be able to hit your photos and music easily, with Windows Media Video streaming support. And you need to either hit your IP manually or use a Dynamic DNS service, but hey, free is free, and look, you just got streaming home video without a Slingbox (plus Music and Photos). [WebGuide]
I know you love your slingbox, but I know you'll agree that it would be pretty cool to stream your media straight from your HTPC...